scripts.mandelbrot.jfl Maven / Gradle / Ivy

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/*
 * An example Jiffle script: draws a binary
 * image of the Mandelbrot set. Adapted from
 * C code at http://warp.povusers.org/Mandelbrot/
 *
 * Author: Michael Bedward
 */

/* We declare variables that we want to remain
 * in scope between pixels in the 'init' block.
 * The functions  width() and height() return
 * the dimensions of the destination area.
 */
init {
  MaxIter = 30;
  MinRe = -2.0;
  MaxRe = 1.0;
  MinIm = -1.2;
  MaxIm = MinIm + (MaxRe-MinRe) * height() / width();
  Re_scale = (MaxRe-MinRe)/(width()-1);
  Im_scale = (MaxIm-MinIm)/(height()-1);
}


/* Calculations performed for each pixel.
 * The functions x() and y() return current
 * pixel coordinates.
 */
c_im = MaxIm - y()*Im_scale;
c_re = MinRe + x()*Re_scale;

Z_re = c_re;
Z_im = c_im;

outside = 0;
n = 0;

/* Jiffle has an 'until' loop construct */
until (n >= MaxIter) {
    Z_re2 = Z_re*Z_re;
    Z_im2 = Z_im*Z_im;

    outside = Z_re2 + Z_im2 > 4;
    breakif( outside );

    Z_im = 2*Z_re*Z_im + c_im;
    Z_re = Z_re2 - Z_im2 + c_re;
    n++ ;
}

/* The variable 'result' represents the
 * destination image (you can use any name
 * you like in your own scripts).
 */
result = outside;